Multi-type Vehicle Routing Problem Under Theinfluence Of Traffic Congestion Posteffect

With the advent of an aging society,the demand for medical supplies is increasing.The rapid fluctuations in demand for medicines and their small batch size,large batches and strong timeliness make it increasingly important to scientifically balance vehicle loading rates and delivery time constraints in the context of increasingly crowded urban traffic.However,in the existing research,it is difficult to meet the needs of the path optimization under the time-consuming congestion index to avoid the current congested road segment.Based on this,this paper introduces the posteffect of traffic congestion and studies the route optimization problem of the point to be distributed under the influence of posteffect.The paper analyzes the impact of the real-time traffic congestion index on the current distribution road segment,and predicts the change of the congestion index of the subsequent road segment and its effect on the delivery time.Real-time dynamic optimization of customer delivery sequence and delivery route during the delivery process.The main research contributions are as follows:Firstly,accorded to the characteristics of current medical logistics distribution,the importance of posteffect of traffic congestion on the delivery time and the importance of balancing delivery time limit and vehicle loading rate are fully considered.The hybrid variable neighborhood search algorithm is designed to dynamically optimize the pre-delivery vehicle assignment and the distribution sequence and route.Finally,the reliability and effectiveness of the algorithm are verified by using standard examples and actual data of a well-known pharmaceutical logistics distribution company.Secondly,proposed the Dijkstra algorithm that uses the cost network pre-processing weight value to balance the delivery time limit and high load rate.The posteffect of traffic congestion makes the original Dijkstra algorithm not directly usable for network analysis.Therefore,the cost network can convert all vehicle assignments corresponding to the current path into weighted directed graphs by cost,and the Dijkstra algorithm can find a vehicle assignment scheme that meets the constraints and has the lowest total cost in the weighted directed graph.Thirdly,assessed the congestion of each road in the network,adjust the vehicle scheduling strategy according to the evaluation result,and dynamically adjust the customerdelivery sequence and delivery path during the delivery process.Full consideration is given to the differences in traffic congestion indices across roads and the impact of local congestion on the overall route.